This paper describes the UK site of the ITSWAP project which is developing ITS services using the Wireless Application Protocol (WAP). The site is situated in Wales and includes several key features aimed at improving travel using the potential of the WAP. ITS services being implemented in Wales include pre-trip traveller information, journey planning, route planning, tourist information, on-trip ...
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The multi-hop, ad-hoc wireless networks of ODMA can be shown to reduce overall transmission power compared with single hop transmission, however, for simple receivers and low user density, the actual capacity of UTRA TDD may be marginally reduced from the maximum non-relaying capacity. This paper analyses the capacity of ODMA in relation to the coverage of a cell. It is shown that after the covera...
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This paper addresses the problem of delivering reliable video information in a world with varying network capacities, an increasing demand in mobility, and frequent occasions of congestion or complete signal loss. A hybrid solution is proposed for the application of handheld wireless videophones with a prioritisation scheme of what information is important and what is not
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One of the prime goals of a reconfigurable terminal is that it shall work on a great range of systems and standards. Amongst the many features that are required to support this inter-system roaming is the ability to detect, discover or identify alternative systems. Having located alternative systems, the terminal then needs the ability to connect to them and also monitor them in order to determine...
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In EGPRS the gain achieved through code combining of erroneous data packets; the so-called incremental redundancy (IR), compared with no IR is highly dependent on successful decoding of the RLC/MAC header. This paper provides-under a simulation environment-the effect of header error on the downlink link level performance of EGPRS when operating in the IR mode. The results are presented in terms of...
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Trends within mobile communications networks are towards more diverse systems which rely increasingly of software components. The UK Virtual Centre of Excellence in Mobile and Personal Communications is researching these trends, and how it will be possible to control these future networks. This paper describes the work in the software dependent systems area of the programme
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This paper addresses the problem of supporting real-time communications in a multihop mobile network using QoS routing, and presents evaluation results on the QoS routing model proposed by Aggelou (see Ph.D. Thesis, University of Surrey, 2001). In the performance experiments, we consider multimedia traffic flows with different QoS types and examine the system performance in various communication e...
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The requirements of 3G and 4G systems dictate that system architectures adapt to various user conditions, i.e. be reconfigurable. The concept of a fully reconfigurable system is fast becoming reality, due to new and advancing enabling technologies. This paper presents two such technologies, the field programmable gate array (FPGA) and field programmable analogue devices (FPAD). These devices provi...
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The minimum mean square error (MMSE) detector, the suboptimal one, takes into account both multiple access interference (MAI) and the background noise, generally provides better probability of error performance than the decorrelating detector. The parallel interference cancellation (PIC) schemes estimates and substracts out all of the MAI for each user in parallel the initial estimates used to be ...
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Traffic planning for multimedia has become more and more significant as new network infrastructures with different characteristics have been introduced lately. The increasing popularity of mobile communications has also drawn much of the attention from the research point of view. Thus, this paper addresses the problem of traffic planning, initiated by this interest, for mobile video communications...
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Most implementations of software definable radio platforms concentrate on reconfiguration of physical hardware via proprietary application programming interfaces. At the networking level, projects such as the Radio API (GloMo) and the IEEE 1520 are prime examples of the efforts to open up the protocol stacks and to introduce open platforms and service programmability. Software reconfigureable radi...
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A number of direction-specific issues on soft coverage analysis and planning along with capacity evaluation and planning, and also in resource management for third generation (3G) systems are discussed. The emphasis is on the differences between the approach in the uplink with that in the downlink
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Beginning with the equalizer algorithm of Ghauri and Slock (1998) we investigate several reduced complexity implementations. We assume that the receiver performs channel estimation (based on the continuously available pilot), and this estimate is used to compute the required equalizer. This computation requires calculation of a matrix inverse, and this is the focus of the complexity reduction. We ...
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In EGPRS, the link adaptation (LA) mechanism, i.e. matching the code rate to the prevailing radio channel condition, is the major element in maximising the throughput of a user and a system throughput as a whole. However, in a practical system perfect LA will not always be possible. This paper investigates-under a simulation environment-the downlink system level performance of EGPRS under perfect ...
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This paper presents a research project that has implemented a Mobile IPv6 enhanced native IPv6 network on which different TCP and UDP based protocols are used. The most important protocol is considered to be the Session Initiation Protocol, which defines the infrastructure and end client behavior for efficient end-to-end session setup. An overview of the project targets is first given and each tec...
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The 3G mobile-IP networks currently being developed will support end-to-end enhanced real-time multimedia services. End-to-end IP enables very high flexibility for transmission over a mobile network. Conversational services require the use of the Real-time Transport Protocol (RTP), which is typically deployed on top of UDP/IP, to facilitate acceptable quality of service at the receiver. The main d...
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A dynamic adding and dropping thresholds based soft handover algorithm proposed for the UTRA system is evaluated through simulations. The simulations are carried out in an UMTS vehicular environment. Two possible handover triggering schemes i.e. received signal power and received Ec/N0, are compared under the propagation conditions, mobility behaviour and various cell loads. The handover performan...
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HIPERLAN/2 is a European-standard high-speed wireless local area network (WLAN) operating in the 5 GHz band. In order to support broadband multimedia communications, it can provide data rates up to 54 Mbps. The HIPERLAN/2 standard specifies a flexible radio-access network that can be used with a variety of core networks, including UMTS. It is likely that HIPERLAN/2 will become an important complem...
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The performance characteristics of the Enhanced General Packet Radio Service (EGPRS) with the focus on radio network dimensioning for the mobile Internet access are presented. The impact of the new modulation and coding schemes (MCSs) and the related link quality control (LQC) functions defined in the EGPRS specifications on the overall system performance and the quality of service (QoS) for the n...
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In this paper some wireless location experiments using CDMA pilot channels are carried out and an estimation technique to improve its positioning accuracy is proposed. Together with the GPS (global positioning system), lots of positioning technologies using existing infrastructure, that is, mobile communication networks, are being researched. Because of the shortage of hearable signals, multipath,...
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The advent of enabling technologies for reconfigurable logic processing requires that investigation into new design methodologies is made before they can be used effectively. This paper presents the design of an FPGA configuration for the decoding of convolutional codes. These codes provide resilience in noisy transmission conditions for many different digital communication systems. The decoder ca...
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A major study conducted during 2000 by the UMTS Forum and subsequently published as a Report [UMTS Forum] assesses the huge market potential of 3G services, taking into account the latest industry revenue forecasts for three key services at the world-wide level. The study has enabled a much better understanding of the implications for launch and adoption of 3G services, and how these will be affec...
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Intermodulation distortion and clipping noise due to laser diode nonlinearity constitute a major source of interference and noise in radio over fibre systems. These noise are known to be signal level dependent. This paper proposes an analytical model for evaluating performance of radio over fibre systems. The numerical results presented showed a 4.5 dB improvement in performance when the effect of...
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